How to measure luggage for carry-on limits

Measure the outside, packed

Airlines measure the bag as it sits in the sizer, not the empty shell and not the manufacturer’s spec. Pack it the way you will fly, close every expansion zipper, then measure.

Soft bags, backpacks and duffels can grow by 2 to 5 cm (1 to 2 in) when full. Hard shells do not grow, but their wheels and handles are often left out of the size printed on the tag.

Three measurements, longest points

Length is the longest side, usually from the bottom of the wheels to the top of the carry handle. Width is across the front. Depth is front to back at the fattest point, including any outside pocket.

Use a tape measure on a flat floor. Stand the bag up, measure height from the floor to the top of the handle. Lay it down, measure width and depth at the widest points.

What counts toward the limit

Wheels, feet, side handles, top handles and outside pockets all count. So does a stuffed front pocket. Airlines with bag sizers (Frontier, Ryanair, Wizz Air, easyJet, Spirit historically) enforce this literally: if it does not drop into the frame, it does not fly for free.

Telescoping handles do not count when fully collapsed, which is how the bag goes into the sizer anyway.

Inches or centimetres

US airlines publish limits in inches, most others in centimetres. 1 inch is 2.54 cm. A 22 × 14 × 9 in bag is 55.9 × 35.6 × 22.9 cm, which is why so many bags are sold as 55 × 35 × 23 cm.

Rounding matters at the margins. A bag sold as 56 cm that measures 57 cm packed is over the 55 cm limit on Lufthansa and Ryanair. Our checker shows the exact margin so you can see how close you are.

Common mistakes

Trusting the tag: manufacturers often list the shell size without wheels. Measuring empty: soft bags grow. Forgetting the second bag: on budget airlines the free item is the small under-seat bag, and the roller you measured is a paid extra.